I too have been having this problem since 1 day after prelaunch… I can get in game mail from heart quests and the such but any mail sent directly to me from a friend or guild mate goes into the abyss.
I’ve submitted multiple tickets to address this issue to no avail. It is seriously blocking progress as I have a very generous guild that like to share ups like bags, items etc and I can not get them.
I had hoped the multiple down times to the mail system would have fixed it, but I guess they like to leave some of us out in the cold. It is now becoming a joke when I log into mumble and the first thing I say is “Who wants to send me a test mail?!” and I never receive it and me and my guildmates have lost several items to the postal service.
Please fix this, it is REALLY frustrating.